CPOE Safety Feature May Delay Care

Action Points

Note that this study suggests that hard stops on certain medication orders can have unexpected adverse consequences even though they are effective -- and should probably only be used in situations where there are no exceptions to a prescribed treatment.

Computerized physician order entry systems with a built-in feature to stop doctors from ordering contraindicated medication combinations could have unintended consequences, researchers found.

In a randomized trial conducted among almost 2,000 clinicians, an electronic hard stop alert reduced concomitant ordering of warfarin and trimethoprim-sulfamethoxazole (Bactrim, Septra) by a significant 88% compared with standard practice, Brian L. Strom, MD, MPH, of the University of Pennsylvania in Philadelphia, and colleagues reported.

But the hard stop alert had to be abandoned and the study terminated early after clinically important treatment delays in four patients who needed immediate drug therapy.

"This emphasizes the need for formal evaluation and monitoring of programmatic interventions rather than simply assuming that they will be effective," Strom and co-authors wrote in the Sept. 27 issue of the Archives of Internal Medicine.

Hard stop warnings are one of the trickiest areas of computerized drug order entry systems, which hospitals have to start implementing to get financial incentives from the government for "meaningful use" of healthcare information technology, noted David W. Bates, MD, MSc, of Brigham and Women's Hospital in Boston.

"Hard stops, although valuable, should be used extremely judiciously, that is, only when there are no exceptions," unlike the one in this study, Bates wrote in an accompanying editorial.

Most hospitals don't have a mechanism to make decisions such as this, perhaps in part because each hospital has had to develop its own solutions, he suggested.

This cannot continue "if the nation is to realize the desired benefits from the enormous investment in healthcare information technology," Bates commented, adding "it will be critical to develop answers to many smaller questions, such as those posed in this study, and to share them widely."

The low-tech answer developed at the University of Pennsylvania's hospital had been for pharmacists to call physicians to warn about the bleeding risk when co-prescribing warfarin and the antibiotic trimethoprim-sulfamethoxazole.

After the hospital implemented computerized physician order entry, the researchers sought to reduce the persistent concurrent prescription of the two drugs.

The alert they developed warned physicians that co-prescription was prohibited except in cases of urgent need of the antibiotic. The alert could be overridden by discontinuing one of the drugs, which would allow the order for the other to be processed; by entering an indication of Pneumocystis carinii pneumonia prophylaxis; or by simply directly calling the pharmacist.

The trial compared prescribing among 1,981 clinicians at two academic medical centers in the system; they were randomized when they ordered the combination to the intervention or to standard practice, in which the pharmacist telephoned prescribers to notify them of the drug interaction and recommended cessation for concurrent warfarin and trimethoprim-sulfamethoxazole orders.

For the primary endpoint, clinicians who got the hard stop alerts reacted as hoped, by not reordering the alert-triggered drug within 10 minutes of the alert in 57.2% of the 194 cases. In the control group, this proportion who reacted to the pharmacist alert as desired was just 13.5%.

After adjustment for provider type and clustering, the odds ratio was 0.12 favoring the intervention (95% confidence interval 0.045 to 0.33).

Although the intervention remained significantly effective at the end of the study period, most of the desired responses occurred in the first three months of the intervention, with the steady decline thereafter "suggesting that the effectiveness of the alert may have started to wear off," Strom and co-authors wrote in the paper.

The pneumonia prophylaxis indication exempted just seven co-prescriptions in the intervention group.

When the researchers looked at the orders entered despite the alerts, they found four cases of appropriate prescribing that were delayed by the intervention.

One incident led to failure to prescribe appropriate trimethoprim-sulfamethoxazole prophylaxis for an otherwise critically ill patient.

Another delayed the initiation of antibiotic therapy recommended by the Infectious Diseases Consultation Service.

The other two cases involved delays in initiation of warfarin therapy.

"The delays in treatment with trimethoprim-sulfamethoxazole were especially concerning from the clinical perspective because this is the single best drug for treating some serious specific infections, and the therapeutic alternatives are not as good," Bates pointed out in his editorial.

The researchers cautioned that they could not weigh the benefits against the harm caused by the intervention because they did not review medical records of every patient who went on to get a simultaneous prescription for both warfarin and the antibiotic nor did they follow up on possible adverse events.

The study was funded in part by the University of Pennsylvania Health System and in part by a cooperative agreement from the Agency for Healthcare Research and Quality.

The researchers reported having no conflicts of interest to disclose.

Bates reported being a co-inventor on a patent held by Brigham and Women's Hospital on the use of decision support software for medical management, licensed to the Medicalis Corp. He holds a minority equity position in and consults for Medicalis, which develops Web-based decision support for radiology test ordering. He is on the clinical advisory board for Zynx, which develops evidence-based algorithms. He is a consultant for Hearst, which develops knowledge resources.

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